Power line communication methods and devices

ABSTRACT

A power line communication method for realizing data communication between at least one first or sending power line communication partner device and at least one second or receiving power line communication partner device. The method checks transmission conditions of a plurality of possible communication channels, thereby generating transmission condition data descriptive for the communication conditions of the respective possible communication channels. Additionally, communication conditions of the plurality of possible communication channels are selected as actual communication conditions based on the transmission condition data.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of and is based upon and claims thebenefit of priority under 35 U.S.C. §120 for U.S. Ser. No. 11/576,634,filed Jan. 23, 2008, the entire contents of which are incorporatedherein by reference. U.S. Ser. No. 11/576,634 is a National Stage ofPCT/EP05/10673, filed Oct. 4, 2005 and claims the benefit of priorityunder 35 U.S.C. §119 from European Patent Application No. 04023603.6filed Oct. 4, 2004.

The present invention relates to power line communication methods anddevices.

More particular, the present invention relates to a power linecommunication method for realizing data transmission or datacommunication between at least one first or sending power linecommunication partner device and at least one second or receiving powerline communication partner device. More specifically, the presentinvention relates to a dynamic frequency domain or FD coexistence methodfor power line communication systems and/or to a dynamic time domain orTD coexistence method for power line communication systems.

Although in recent years wireless communication technologies became moreand more important power line communication networks and power linecommunication systems are still of interest and they participate incertain technology strategies. However, achieving a high degree ofreliability is still a major task in the development and progress ofpower line communication technology.

Additionally, the following has to be noted:

In the field of communication arrangements and communication networksdifferent kinds of devices for information exchange are often involved.For instance, so called power line communication modems or power linecommunication modem devices or PLC modems or PLC modem devices may beused which are adapted and designed to use power lines as acommunication channel or a part thereof when communicating withrespective communication partner devices.

Nowadays, known PLC modems in communication arrangements orcommunication networks of the art allocate a predefined communicationspectrum of a possible communication frequency domain in a fixed manner.Therefore known communication schemes using PLC modem devices are beyondfrom being flexible. This is in particular a disadvantage in cases wherethe predefined communication spectrum with respect to a givencommunication channel suffers from low communication capabilities orcommunication features for instance because of signal distortions,signal damping, and/or noise taking place in the chosen communicationchannel and the predefined and selected communication spectrum.

It is an object underlying the present invention to provide a power linecommunication method in which disturbances of power line communicationbetween power line communication partner devices by interferences fromother power line communication systems or other systems or from noisesources can be reduced in a simple and reliable manner in order toincrease the communication quality and the communication reliability aswell as the data throughput possible via power line communicationnetwork strategies.

There are two concepts within the scope of the present invention.

-   -   According to a first concept of the present invention, the        object underlying the present invention is achieved by a power        line communication method with the features of independent claim        1. The object is further achieved by a system for power line        communication, a device for power line communication, a computer        program product, and a computer readable storage medium        according to independent claims 17, 18, 34, and 35,        respectively. Preferred embodiments of the method and the device        for power line communication are within the scope of the        respective dependent sub-claims.

In the following, the inventive method for power line communicationaccording to the invention's first concept is described.

The inventive method for power line communication—according to theinvention's first concept—is adapted in order to realize datacommunication between at least one first or sending power linecommunication partner device and at least one second or receiving powerline communication partner device. The inventive method comprises a step(a) of checking transmission conditions of a plurality of possiblecommunication channels between said at least one first or sending powerline communication partner device and said at least one second orreceiving power line communication partner device, thereby generatingtransmission condition data which are descriptive for the communicationconditions of the respective possible communication channels. Theinventive method further comprises a step (b) of selecting communicationconditions of the plurality of possible communication channels as actualcommunication conditions based on said transmission condition databetween said at least first or sending power line communication partnerdevice and said at least one second or receiving power linecommunication partner device.

It is therefore a key idea of the present invention to monitortransmission conditions or receiving conditions of possiblecommunication channels between power line communication partner devicesbetween which a data communication or a data transmission shall beestablished or is in progress. According to the present invention thetransmission conditions are described by transmission condition data.Based on said transmission condition data communication conditions withrespect to the plurality of possible communication channels are selectedor chosen as actual communication conditions for the actualcommunication to be established or for the actual communication inprogress. According to these measures the quality of data communicationor data transmission between power line communication partner devicescan be maintained or increased by selecting a communication channel orby choosing the communication conditions which make possible a highquality of data communication or data transmission.

This means in other words, that by looking for possible foreigninterferences and avoiding the same by avoiding respective channels,frequency bands, frequency spectra and/or time slots and/or by reducingtransmission gain/power not only other PLC communicating partner devicesare left undisturbed but also by the same measures interferences withcommunicating systems of other types—e.g. outside the PLC field and forinstance amateur, AM or DRM radio services—are avoided or least reduced.

Said transmission condition data may preferably be generated in order todescribe at least one of the group comprising a signal to noise ratio,time slots, frequency bands, channel capacities, interference signalsfrom power line communication partner devices of said power linecommunication system or of other systems of possible power linecommunication channels.

Alternatively or additionally, said actual communication conditions maybe chosen in order to effect and select at least one of the groupcomprising a frequency band, a time slot, a signal modulation scheme andan emission power of a possible or said actual communication channel ofthe plurality of possible communication channels between said at leastone first or sending power line communication partner device and said atleast one second or receiving power line communication partner device.

Said step (a) of checking said transmission conditions may preferably becarried out repeatedly.

Additionally or alternatively, said step (a) of checking transmissionconditions may be carried out during a process of data communication inprogress between said at least one first or sending power linecommunication partner device and said at least one second or receivingpower line communication partner device.

Said step (b) of selecting said communication conditions may preferablybe carried out repeatedly.

Additionally or alternatively, said step (b) of selecting saidcommunication conditions is carried out during a process of datacommunication and progress between said at least one first or sendingpower line communication partner device and said at least one second orreceiving power line communication partner device, in order to changeits communication conditions for maintaining or increasing the actualdata communication quality of the data communication between said atleast one first or sending power line communication partner device andsaid at least one second or receiving power line communication partnerdevice in progress.

It may be of advantage that said actual communication conditions arechosen according to a given threshold criterion, in particular withrespect to at least one of said transmission parameters.

Additionally or alternatively, said actual communication conditions maybe chosen in order to realize a best data communication, in particularwith respect to a given threshold criterion, in particular with respectto at least one of said transmission parameters.

Further, the signal emission for data communication between said atleast one first or sending power line communication partner device andsaid at least one second or receiving power line communication partnerdevice may be reduced or avoided by said at least one first or sendingpower line communication partner device for frequency bands in whichsaid at least one second or receiving power lien communication partnerdevice does not listen and/or in which foreign sending devices or noiseare present.

Further advantageously, the signal emission power for data communicationbetween said at least one first or sending power line communicationpartner device and said at least one second or receiving power linecommunication partner device may be set in order to fulfill givenemission power limit requirements with respect to chosen emissionfrequency bands.

Such a setting may be achieved based on radiated signals measured e.g.via an antenna and/or based on signals measured via an conducting path:FIG. 17. In the situation shown in FIG. 17 the evaluating and estimatingunit EEU receives both signal types. i.e. information from bothinterfaces, namely the antenna interface AI and the power line interfacePLI.

The data communication between said at least one first or sending powerline communication partner device and said at least one second orreceiving power line communication partner device may preferably beestablished according to a media access control or MAC structure.

A channel capacity may be evaluated according to Shannon's law and inparticular according to the following formula (1):

$\begin{matrix}{C = {\int_{t_{start}}^{t_{stop}}{\int_{f_{start}}^{f_{stop}}{l\ {d\left( {1 + {SNR}} \right)}{\mathbb{d}f}\ {\mathbb{d}t}}}}} & (1)\end{matrix}$wherein C denotes the channel capacity, t denotes the time variable fordata transmission, t_(start) denotes the starting time, t_(stop) denotesthe stopping time, f denotes the frequency variable, f_(start) denotesthe starting frequency, f_(stop) denotes the stopping frequency,ld(•)denotes the dual logarithmic function, and SNR denotes therespective signal-to-noise-ratio.

According to a further additional or alternate embodiment, for aplurality of time gaps with respective starting times t_(start,l), . . ., t_(start,n) and stopping times t_(stop,l), . . . , t_(stop,n)fulfilling the conditions t_(start,j)≦t_(start,j+1),t_(stop,j)≦t_(stop,j+1), and t_(start,j)<t_(stop,j) for j=1, . . . , nand/or for a plurality of frequency gaps with respective startingfrequencies f_(start,l), . . . , f_(start,m) and stopping frequenciesf_(start,l), . . . , f_(start,m) fulfilling the conditionsf_(start,k)≦f_(start,k+1), f_(stop,k)≦f_(stop,k+1), andf_(start,k)<f_(stop,k) for k=1, . . . , m a full channel capacityC_(full) may be evaluated according to the following formula (2a):

$\begin{matrix}{C_{full} = {\sum\limits_{j = 1}^{n}{\sum\limits_{k = 1}^{m}C_{j,k}}}} & \left( {2a} \right)\end{matrix}$wherein C_(j,k) denotes the partial channel capacity for the j^(th) timegap and the k^(th) frequency gap and is determined according toShannon's law and in particular according to the following formula (2b):

$\begin{matrix}{C_{j,k} = {\int_{t_{{start},j}}^{t_{{stop},j}}{\int_{f_{{start},k}}^{f_{{stop},k}}{l\ {d\left( {1 + {SNR}} \right)}{\mathbb{d}f}\ {\mathbb{d}t}}}}} & \left( {2b} \right)\end{matrix}$wherein t denotes the time variable for data transmission, f denotes thefrequency variable, ld(•) denotes the dual logarithmic function, and SNRdenotes the respective signal-to-noise-ratio.

Thereby a TD approach with a plurality of time gaps with respectivestarting times t_(start,l), . . . , t_(start,n) and stopping timest_(stop,l), . . . , t_(stop,n) and/or a FD approach with a plurality offrequency gaps with respective starting frequencies f_(start,l), . . . ,f_(start,m) and stopping frequencies f_(stop,l), . . . , f_(stop,m) isrealized and the full available channel capacity or channel capabilityis the some of the respective partial channel capacities C_(j,k.)

Additionally or alternatively, a signal to noise ratio may be determinedaccording to the following formula (3):SNR=PSD_(feed)−ATT−NPSD_(receive)  (3)wherein SNR denotes the respective signal to noise ratio, PSD_(feed)denotes the feeding power spectral density, which is in particular knownto all modems, NPSD_(receive) denotes the noise power spectral densityat a receiver, which is in particular measured by the receiving powerline communication partner device, and ATT denotes the attenuation of asignal, in particular between said first or sending power linecommunication partner device and said second or receiving power linecommunication partner device.

According to a further preferred embodiment of the inventive method forpower line communication a plurality of power line communication systemsmay be managed, in particular each having a plurality of power linecommunication partner devices and/or each without inter systemcommunication between each of said systems of said plurality of powerline communication systems.

In the following, the inventive device for power line communicationaccording to the invention's first concept is described.

It is still a further aspect of the present invention to provide a powerline communication system, which is adapted and/or arranged and whichhas means in order to realize the inventive method for power linecommunication.

It is still a further aspect of the present invention to provide a powerline communication device which is adapted and/or arranged and which hasmeans in order to realize a and/or to participate in a method for powerline communication according to the present invention.

Also, a computer program product is provided according to the presentinvention which comprises computer means which is adapted and/orarranged in order to realize a method for power line communicationaccording to the present invention and the steps thereof when it isexecuted on a computer, a digital signal processing means or the like.

Finally, a computer readable storage medium comprising a computerprogram product according to the present invention.

These and further aspects of the present invention will be furtherdiscussed in the following:

The present invention inter alia relates to a dynamic FD and/or TDcoexistence method for power line communication system or PLC systems.

Power line networks are open networks. Signals from PLC system installedin adjacent flats may crosstalk to other PLC systems. Data—throughput ofboth systems is degraded due to this interference. This invention showsa method to share resources in Time and Frequency Domain that bothsystems do not interfere. Using this coexistence method, the totalthroughput of both systems is higher than if there is interference ofthe communication signals. There is no compatibility or data exchangeneeded between PLC systems.

Today, there is no coexistence present in PLC communication. PLC modemsuse permanent frequency allocations with maximum power possible. Signalsof modems various vendors interfere and all systems have lower datathroughput.

1 Time and Frequency Diversity for Known and Unknown CommunicationSystems in a Quasi Static Channel

1.1 Introduction

Power line networks are open networks. The wires inside a building areconnected to the transformer station. Each transformer station isconnected to many houses. Often houses are daisy chained along theoverhead cabling. Even inside a building several flats or living unitsare connected in the meter room or fuse cabinet. PLC signals crosstalkfrom one living unit to another. The cross talking signals areattenuated by the power meters or the distance between the living unitsor the buildings. The longer the distance, the less is the risk of theinterference of a communication. Statistically in most cases aconnection from one outlet inside a living unit to another outlet inanother living unit is more attenuated than a connection between twooutlets inside a flat. But in a very few cases the opposite was found.For the interference cases, a coexistence mechanism is needed.Theoretically coexistence problems can be solved in Time or Frequencydomain.

1.2 Scenario

For example inside Flat 1 there is a power line communication or PLCcommunication from P1 (Plug 1) to P10. In the adjacent Flat, there is acommunication from P15 to P21. PLC communication system from Flat 2interferes to the PLC system installed in Flat 1.

The current invention shows a mechanism, how to minimize the influenceof interference between the two PLC systems that are based on the sameor on different architecture.

1.3 General PLC System Targets

-   -   1. Two outlets that want to communicate to each other are making        use of the best possible communication link in the time- and        frequency-domain    -   2. The communication link between two outlets are occupying only        the undisturbed capacity in frequency and time        1.4 Centralized Medium Access Control or MAC Overview

The proposed invention is inter alfa intended for centralized MACarchitectures, where a central controller is responsible for thecoordination of the time slot (channel) assignments for each MAC frame.A centralized MAC frame is typically divided into the following phases:

-   -   A broadcast phase where the central controller sends frame        synchronization and resource allocation information (time slot        or channel assignments) to the listening terminals.    -   A downlink phase where data is sent from the central controller        to one or more of the listening terminals.    -   An uplink phase where terminals send data to the central        controller.    -   Optionally, a direct link phase where terminals send data        directly to other terminals.    -   A resource request phase where terminals may requests resource        reservations in a random access fashion, i.e. all terminals        content for the medium during this phase.        1.5 Adaptive OFDM Overview

According to a preferred embodiment of the present invention PLC may useadaptive modulation schemes according to the current channel conditions.OFDM as a modulation scheme that consists of many orthogonalsub-carriers might be extended in a way that each sub-carrier can beadapted to its channel characteristic: Sub-carriers with good conditionschoose high modulation scheme, allowing a high bit rate throughput.Sub-carriers with bad conditions choose a more robust modulation scheme,resulting in a lower bit rate throughput. Moreover, sub-carriers withvery bad conditions can be left out. FIG. 3 shows an example ofavailable SNR in a PLC channel: The y-axis represents the available SNR,the x-axis the frequency. Frequencies with high SNR choose modulation upto 1024 QAM. Decreasing SNR results in more robust modulation schemes,down to QPSK or even BPSK. Areas with very low SNR are notched out.

1.6 Allocation of a Communication Link Between Two Outlets in a FirstFlat 1

A further embodiment of the invention my be realized at least in partaccording to the following processing steps:

-   -   1. P10 is monitoring the amplitude or field strength over the        PLC frame period or the PLC MAC frame period within the        frequency band, e.g. 4 MHz to 30 MHz. P10 detects the time slot        which has minimum interferer.    -   2. P10 requests the data from P1 to be transmitted at the best        time slot within one PLC frame. This may be coordinated by a        master of centralized MAC.    -   3. P1 sends 1st initial data packet with robust modulation        pattern at defined time slot to P10.    -   4. P10 defines the frequency dependent modulation pattern out of        the received signal from P1 and the measured interferer and        noise (SNR calculation).    -   5. P10 requests data as ongoing payload from P1 with specific        modulation pattern at specific time slot within the PLC frame.    -   6. P1 sends data to P10 with requested modulation pattern.

If P10 detects difficulties in time or frequency with the received datafrom P1, immediate retransmission will be requested at higher layer.Then P10 requests further data at a new timeslot within the PLC frameand/or with a new modulation pattern from P1.

1.7 Case 1: PLC System of a Second Flat 2 is a Fully Unknown Interferer

There is only limited gain from changing the time slot because timeselective interferers (transmission from P15 to P21) are difficult topredict. However there is a good chance to avoid this interfere at leastfor some time.

1.8 Case 2: PLC System of a Second Flat 2 is a Known PLC Interferer,e.g. a PLC System with the Same System Architecture as the PLC System ina First Flat 1

Changing the time slot provides a big advantage even if the two PLCsystems are of first and second flats 1 and 2 not fully synchronizedbecause the relative movement of the PLC frames is expected to be veryslow as the clock deviation is very small.

1.9 Calculating Channel Capacity for Time Domain Approach

Using Shannon's law the channel capacity C within a time frame can becalculated according to the following formula (1):

$\begin{matrix}{C = {\int_{t_{start}}^{t_{stop}}{\int_{f_{start}}^{f_{stop}}{l\ {d\left( {1 + {SNR}} \right)}{\mathbb{d}f}\ {{\mathbb{d}t}.}}}}} & (1)\end{matrix}$

In a TD approach with a plurality of time gaps with respective startingtimes t_(start,l), . . . , t_(start,n) and stopping times t_(stop,l), .. . , t_(stop,n) and/or a FD approach with a plurality of frequency gapswith respective starting frequencies f_(start,l), . . . , f_(start,m)and stopping frequencies f_(stop,l), . . . , f_(stop,m) the fullavailable channel capacity or channel capability is the sum of therespective partial channel capacities C_(j,k).

In this case, a plurality of time gaps with respective starting timest_(start,l), . . . , t_(start,n) and stopping times t_(stop,l), . . . ,t_(stop,n) fulfilling the conditions t_(start,j)≦t_(start,j+1),t_(stop,j)≦t_(stop,j+1), and t_(start,j)<t_(stop,j) for j=1, . . . , nand/or for a plurality of frequency gaps with respective startingfrequencies f_(start,l), . . . , f_(start,m) and stopping frequenciesf_(stop,l), . . . , f_(stop,m) fulfilling the conditionsf_(start,k)≦f_(start,k+1), f_(stop,k)≦f_(stop,k+1), andf_(start,k)<f_(stop,k) for k=1, . . . , m are given. The full channelcapacity C_(full)/is then evaluated according to the following formula(2a):

$\begin{matrix}{C_{full} = {\sum\limits_{j = 1}^{n}{\sum\limits_{k = 1}^{m}C_{j,k}}}} & \left( {2a} \right)\end{matrix}$wherein C_(j,k) denotes the partial channel capacity for the j^(th) timegap and the k_(th) frequency gap and is determined according toShannon's law and in particular according to the following formula (2b):

$\begin{matrix}{C_{j,k} = {\int_{t_{{start},j}}^{t_{{stop},j}}{\int_{f_{{start},k}}^{f_{{stop},k}}{l\ {d\left( {1 + {SNR}} \right)}{\mathbb{d}f}\ {\mathbb{d}t}}}}} & \left( {2b} \right)\end{matrix}$wherein t denotes the time variable for data transmission, f denotes thefrequency variable, ld(•) denotes the dual logarithm function, and SNRdenotes the respective signal-to-noise-ratio.

The signal-to-noise-ration SNR may be calculated a calculated accordingto the following formula (3):SNR=PSD_(feed)−ATT−NPSD_(receive).  (3)

PSD_(feed) is the feeding power spectral density and is known to allmodems. NPSD_(receive) is the noise power spectral density at thereceiver and is measured by the receiving modem. ATT denotes theattenuation which is measured by a pair of PLC modems or PLC devices.

In Time Domain approach the full available frequency spectrum is used.The capability of a transmission is sum of capability of all timeframes.

1.10 Freeing Useless Frequency Bands

All PLC systems must be able to detect noise on the power line networkand to omit the disturbed frequencies from their communication by e.g.notching OFDM carriers. Only frequencies with good SNR shall be used forthe communication. Other frequencies (with bad SNR) shall be omitted.The receiving modem measures the available SNR that becomes thereference for selecting the carriers for communication at thetransmitter site.

In the example of FIG. 1 there is following an attenuation from P1 toP10 as is shown in FIG. 5. The transmitted signal has 0 dB attenuationat P1. At P10 the receiving signal is attenuated as shown in FIG. 5.

In the following these and further aspects of the present invention willbe explained in more detail based on preferred embodiments of thepresent invention and by taking reference to the accompanying figureswhich schematically demonstrate aspects of the present invention. Thered curve in FIG. 6 shows the attenuation from P15 to P10, which isidentical to the interference to P10 caused by the communication betweenP15 and P21. The example in FIG. 6 shows a rare case, where theinterference signals from outside are in meridian less attenuated thanthe signals from inside the Flat. Even under this constrains, there aresome frequency ranges where the desired connection has less attenuationthan the interfering signals.

At frequencies where the interfered signal is higher than the desiredsignal, e.g. 4 to 10 MHz, 13 to 16 MHz and 20 to 30 MHz, nocommunication is possible from P1 to P10. So these frequencies shall beomitted, without loosing any bit rate. After notching these frequenciesthe received signal looks like shown in FIG. 7.

The blue areas mark the SNR that can be used by the communication fromP1 to P10. As a consequence the freed frequencies can be used by otheradjacent PLC systems, e.g. PLC system in Flat 2. In case Flat 2 operatesin the same way as the system in Flat 1 the communication from P15 toP21 could omit those frequencies used by flat 1. This offers an extendedSNR for flat 1 and therefore higher bit rate (see FIG. 8).

If this coexistence mechanism is implemented to power line modems ordevices, the dynamic notching for SW radioprotection is alreadyincluded, because frequencies with low SNR caused by SW broadcastsignals will be omitted.

1.11 Calculating the Channel Capacity for Frequency Domain Approach

Again, according Shannon's law shown in formula (1) the channel capacityC may be calculated. Here one or several frequency spans are used forthe communication permanently.

1.12 Power Back Off

Similar behavior as described for the frequency domain can be applied tothe transmitted power level in order to reduce the interferencepotentials.

For the possible calculation of the channel capability C according toformulas (1) and (2) the value of PSD_(feed) is reduced, the fullavailable spectrum is used permanently.

Actual communication conditions may be chosen in order to effect andselect at least one of the group comprising a frequency band, a signalmodulation scheme, a time slot, an emission power or transmission power,transmission gain and reception gain each of a possible or of saidactual communication channel Ch1, . . . , Chn of the plurality ofpossible communication channels Ch1, . . . , Chn between said at leastone first or sending power line communication partner device P1 and saidat least one second or receiving power line communication partner deviceP10.

The power back off process may be designed in order to avoidinterference with other power line communication services and/or radioservices by reducing transmission power fed or to be fed.

In said power back off process transmission power fed or to be fed maybe reduced to a minimum value or range which is still sufficient and/orappropriate for enabling and/or maintaining loss free or essentiallyloss free power line communication.

Said power back off process may be performed individually for one or aplurality of different channels and/or carriers.

Said power back off process may also be performed on a distinct channeland/or carrier if an actual signal to noise ratio of said given channeland/or carrier is better than a signal to noise ratio necessary for anactual bit loading in said given channel and/or carrier.

Power line communication may be performed with a transmission gainand/or transmission power on the transmission side which fits to atleast one of a maximum sensitivity, maximum input gain and minimum inputattenuation on a receiving side.

Said transmission gain and/or transmission power of said transmissionside may be at least one of set, requested, communicated and negotiatedby or with said receiving side.

Said power back off process may be performed in order to adjusttransmission gain and/or transmission power in accordance to at leastone of attenuations and distances to be bridged between devices undercommunication, in particular in order to reduce said transmission gainand/or transmission power for comparable short distances.

Transmission gain and/or transmission power may be raised in order toincrease a possible quality of service value or QoS value for quality ofservice data streams or QoS streams.

Information and/or signal components which need a higher QoS value maybe assigned and mapped to certain carriers and said certain carriers maybe given an increased amplitude and/or transmission power in the powerline communication process.

Said increased amplitude and/or transmission power for the power linecommunication process may be achieved by operating a respective spectralinterleaver device in order to assign and map said information and bitswhich need a higher QoS value to said respective carriers.

1.13 Device and Components View of the Invention's Embodiments

In FIG. 9 for an embodiment of an inventive receiving PLC partner deviceP10 an AFE or analog front end is comprised and the calculation of bestamplitude, time and frequency span is novel in this invention whencompared to the state of the art PLC modems today. The respectiveinformation may be send back to the transmitting modem or device.

In FIG. 10 for an embodiment of an inventive sending PLC partner deviceP1 the PSD or power spectral density is set and the transmitting modemor PLC device gets the information about best power settings, timing andfrequency allocations. This information is forwarded to the modules inthe MAC and physical layers MAC and PHY. The MAC layer MAC isresponsible when the PLC modem or device P1 transmits data. The physicallayer PHY places the notches or carriers of the OFDM transmissionaccording to the best throughput conditions.

1.14 Conclusion

Some properties of state of the art communication technology are listedin the following:

-   -   1. Make use of coding together with time and frequency        interleaving within a channel that is varying over time and        frequency. Useful and efficient for fast changing channels    -   2. State of the art OFDM systems, e.g. wireless systems, do not        use the benefits of quasi-static channels like PLC.    -   3. Allocating fixed frequency blocks for different users        realizes coexistence.    -   4. Allocating fixed time slots for different users realizes        coexistence (synchronized systems are needed).    -   5. Having enough distance to other users enables coexistence        (strong attenuation between users)

Some possible properties of the new approach are listed in thefollowing:

-   -   1. System may be realized adapt fast to changing channels. The        overhead is only spend during the changes of the channel. This        is efficient for quasi static channels.    -   2. Unused frequency blocks may become available for others.    -   3. Fully synchronized systems may be not required to make use of        free timeslots.    -   4. System can make use of the specific channel conditions        between nodes and external or outside interference.    -   5. The coexistence mechanism (Frequency Domain, Time Domain or        Power Domain) that provides maximum channel capacity or channel        capability shall be used for the communication.    -   According to a second concept of the present invention, the        object underlying the present invention is achieved by a method        for operating a PLC modem device with the features of        independent claims 36 and 37. Additionally the object is        achieved by a method for operating a communication arrangement,        a PLC modem device, a communication arrangement, a computer        program product, as well as with a computer readable storage        medium according to the characterizing features as recited in        the claims. Preferred embodiments of the method and the device        for power line communication are within the scope of the        respective dependent sub-claims.

According to the present invention one the one a method for operating aPLC modem device in a communication arrangement is proposed wherein thepresence of interferences from other PLC modem devices or from radioservices is monitored and wherein in the case that interferences fromother PLC modem devices or from radio services are detected power linecommunication is at most performed on communication channels orcommunication spectra where said interferences from other PLC modemdevices or from radio services are not detected. Thereby, simultaneouslyinterferences to and from other PLC modem devices and radio services areavoided.

The method for operating a PLC modem device according to the presentinvention is adapted in particular for PLC modem device operation in acommunication network or in a communication arrangement. The inventivemethod on the other hand comprises a step of generating and/or providingcommunication quality data and/or of at least one communication channel,a step of determining at least communication spectrum data andcommunication channel data, a step of determining and/or selecting acommunication spectrum and/or a communication channel, and a step ofcommunicating with at least one communication partner device via saidselected communication channel and/or said selected communicationspectrum. The respective communication quality data are generated and/orprovided with respect to at least one communication channel between saidPLC modem device and at least one communication partner device. Saidcommunication quality data are descriptive at least for communicationcapabilities, a communication quality and/or for communication featuresat least of said at least one communication partner device and/or ofsaid at least communication channel. Said communication spectrum dataand/or said communication data are determined based on saidcommunication quality data and they are descriptive for at least onecommunication spectrum for said PLC modem device and/or for said atleast one communication channel each of which with respect to said atleast one communication partner device. Said communication spectrumand/or said communication channel are determined and/or selected from atleast one communication channel each of which on the basis of saidcommunication spectrum data and/or said communication channel data.

It is therefore a basic idea of the present invention to enable a PLCmodem device to generate and/or to provide data describing communicationcapabilities, communication quality and/or communication features of atleast one communication partner device and/or of at least onecommunication channel for communication with said at least onecommunication partner device. These data are called communicationquality data as they are described in the broad sense the quality ofpossible communication.

The invention can also be applied to PLC technology. Also, wirelesstransmissions and technologies are thinkable.

The invention preferably affects all modems participating to thecommunication. Or even these modems who are not participating to thecommunication or belonging to an other system are affected, because ofinteroperability or coexistence. A PLC system comprises several modemscommunicating to each other. There might be several PLC systemsconnected to one Power line.

By a measurement process at least one of possible communication channelsand communication spectra are monitored within said step of at least oneof generating and providing said communication quality data.

In said step of at least one of determining and selecting at least oneof a communication spectrum and a communication channel at least one ofan actual communication spectrum and an actual communication channel isselected and chosen for said step of communicating for which acomparable low interference from signal sources or signals other thanthe communication partner devices associated in said step communicatingand the signal stemming there from, respectively, may be given.

Thereby avoiding and de-allocating partly or completely least one ofcommunication spectra and communication channels of devices and servicesother than devices and services associated in said step of communicationcan be achieved.

Thereby avoiding and de-allocating partly or completely at least one ofcommunication spectra and communication channels associated with one ora plurality of amateur, AM or DRM radio services can be achieved.

This means in other words, that by looking for possible foreigninterferences and avoiding the same by avoiding respective channels,frequency bands, frequency spectra and/or time slots and/or by reducingtransmission gain/power not only other PLC communicating partner devicesare left undisturbed but also by the same measures interferences withcommunicating systems of other types—e.g. outside the PLC field and forinstance amateur, AM or DRM radio services—are avoided or least reduced.

Said measurement process may be performed wirelessly.

Said measurement process may be performed by means of an antenna as apart of said PLC modem device.

Said measurement process may also be performed by wire.

Said measurement process may further be performed by means of a sensormeans connected to a respective communication wire means.

The actual communication conditions may be chosen in order to effect andselect at least one of the group comprising a frequency band, a signalmodulation scheme, a time slot, a transmission power, a transmissiongain and a reception gain each of a possible or of said actualcommunication channel of the plurality of possible communicationchannels between said at least one first or sending power linecommunication partner device and said at least one second or receivingpower line communication partner device.

Further, a power back of process may be comprised in order to avoidinterference with other power line communication services and/or radioservices by reducing transmission power fed or to be fed.

In said power back off process transmission power fed or to be fed maybe reduced to a minimum value or range which is still sufficient and/orappropriate for enabling and/or maintaining loss free or essentiallyloss free power line communication.

Said power back off process may be performed individually for aplurality of different channels and/or carriers.

Said power back off process may be performed on a distinct channel andcarrier if an actual signal to noise ratio of said given channel and/orcarrier is better than a signal to noise ratio necessary for an actualbit loading in said given channel and/or carrier.

Power line communication may be performed with a transmission gain andtransmission power on the transmission side which fits to at least oneof a maximum sensitivity, maximum input gain and minimum inputattenuation on a receiving side.

Said transmission gain and/or transmission power of said transmissionside may be at least one of set, requested, communicated and negotiatedby or with said receiving side.

Said power back off process may be performed in order to adjusttransmission gain and/or transmission power in accordance to at leastone of attenuations and distances to be bridged between devices undercommunication, in particular in order to reduce said transmission gainand/or transmission power for comparable short distances.

Information and/or signal components which need a higher QoS value maybe assigned and mapped to certain carriers and said certain carriers maybe given an increased amplitude and/or transmission power in the powerline communication process.

Said increased amplitude and/or transmission power for the power linecommunication process may be achieved by operating a respective spectralinterleaver device in order to assign and map said information and bitswhich need a higher QoS value to said respective carriers.

The transmission gain and/or transmission power may be raised in orderto increase a possible quality of service value or QoS value for qualityof service data streams or QoS streams.

Said process of raising said transmission gain and/or transmission powermay be performed in a way still enabling and/or maintaining avoiding andde-allocating partly or completely least one of communication spectraand communication channels of devices and services other than devicesand services associated in said step of communication and/or avoidingand de-allocating partly or completely at least one of communicationspectra and communication channels associated with one or a plurality ofamateur, AM or DRM radio services.

It is a further idea of the present invention to use said communicationquality data so as to determine communication spectrum data and/orcommunication channel data on the basis of said communication qualitydata. Said communication spectrum data and/or said communication channelare chosen to be descriptive for at least one communication spectrum forsaid PLC modem device and/or for said at least one communication channeleach of which in relation to said at least one communication partnerdevice. Based on said communication spectrum data and/or on saidcommunication channel data a communication spectrum is determined and/orselected for a possible communication with said communication partnerdevice. Additionally or alternatively said communication spectrum dataand/or said communication channel data are used as a basis fordetermining and/or for selecting a respective communication channel toofor realizing said communication process between said PLC modem deviceand said communication partner device.

According to a further or alternative aspect of the present inventionthe inventive method comprises a step of detecting at least onecommunication partner device which is connected to said PLC modem devicevia at least one communication channel.

Additionally or alternatively, also a step of detecting said at leastone communication channel between said PLC modem device and at least onecommunication partner device itself may be comprised.

In a preferred embodiment of the inventive method for operating a PLCmodem device said step of generating and/or providing communicationquality data comprises a process of determining and/or measuring noiseof said at least one communication channel, in particular of a powerline thereof.

Further additionally or alternatively said step of generating and/orproviding communication quality data may comprise a process ofdetermining and/or measuring a signal attenuation, a signal transmissionlevel, a distance of said PLC modem device to said communication partnerdevice and/or a signal-to-noise-ratio or with respect to said at leastone communication channel, in particular of or with respect to a powerline thereof. The case of determining and/or measuring asignal-to-noise-ratio this may be realized based on said noise,attenuation, signal transmission level, distance determined and/ormeasured.

It is further preferred to analyze for said at least one communicationpartner device a plurality of communication channels, in particular allavailable communication channels for said communication partner device,in particular within said steps of detecting said at least onecommunication partner device and/or said at least one communicationchannel, within said step of generating and/or providing saidcommunication quality data, within said step of determining at leastsaid communication spectrum data and/or said communication channel data,and/or within said step of determining and/or selecting saidcommunication spectrum and/or said communication channel.

According to a further and advantageous embodiment of the inventivemethod for operating a PLC modem device a communication spectrum and/ora communication channel may be selected and/or used which are notsimultaneously used or allocated by communication processes of and/orbetween other communication partner devices within said communicationnetwork or communication arrangement, in particular within said step ofdetermining and/or selecting a communication spectrum and/or acommunication channel.

According to a further preferred embodiment of the inventive method fora communication channel having or realizing a comparable larger orcomparable large communication distance between said PLC modem deviceand said selected communication partner device a comparable lower orcomparable low frequency range is chosen for said communicationspectrum, in particular within said step of determining and/or selectinga communication spectrum.

Additionally or alternatively for a communication channel having orrealizing a comparable shorter or comparable short communicationdistance between said PLC modem device and said selected communicationpartner device a communication spectrum with a comparable high orcomparable higher frequency range is chosen, in particular within saidstep of determining and/or selecting a communication spectrum.

A further preferred embodiment of the inventive method is provided,wherein a process of checking the presence, existence and/or activity ofother and external radio sources and/or radio services is performed, inparticular within said step of generating and/or providing communicationquality data, within said step of determining at least communicationspectrum data and/or communication channel data, and/or within said stepof determining and/or selecting a communication spectrum and/or acommunication channel, wherein said communication quality data, saidcommunication spectrum data, said communication channel data, saidcommunication spectrum and/or said communication channel are chosen orselected in order to avoid spectral ranges where other and externalradio sources and/or radio services exist, are present and/or areactive, in order to reduce and/or avoid disturbances and/orinterferences with, to and/or from other and external radio sourcesand/or radio services.

Still a further preferred embodiment is proposed, wherein within saidprocess of checking the presence, existence and/or activity of other andexternal radio sources and/or radio services PLC modem devices snoop inthe air if there are any radio services and/or radio sources availableand wherein—if a relevant service and/or source is found at anyfrequency location—the respective frequency band is omitted in powerline communication.

Additionally or alternatively it is proposed that said process ofchecking the presence, existence and/or activity of other and externalradio sources and/or radio services is performed in a wireless mannerand/or in a wired manner.

It is a further aspect of the present invention to provide a method foroperating a communication arrangement or a communication network, saidcommunication arrangement or said communication network comprising aplurality of PLC modem devices, wherein for each of said PLC modemdevices the method for operating a PLC modem device according to thepresent invention is performed.

Thereby by fair avoidance a process avoiding and de-allocating at leastone of communication spectra and communication channels associated withat least one of amateur, AM and DRM radio services can be achieved.

An alternative or additional embodiment is provided, wherein apre-defined reference signal is generated by at least one PLC modemdevice and transmitted via at least one available communication channel,wherein possible communication partner devices measure said pre-definedreference signal via said at least one available communication channeland/or analyze the respective measurement data, wherein based on saidmeasurements said communication quality data, said communicationspectrum data, said communication channel data, said communicationspectrum and/or said communication channel are chosen or selected, inparticular in order to avoid spectral ranges where other and externalradio sources and/or radio services exist, are present and/or areactive.

Still an alternative or additional embodiment is provided, wherein apre-defined reference signal is generated by at least one PLC modemdevice and transmitted via at least one available communication channel,wherein possible communication partner devices measure said pre-definedreference signal via channels other than said available communicationchannels and/or analyze the respective measurement data, wherein basedon said measurements said communication quality data, said communicationspectrum data, said communication channel data, said communicationspectrum and/or said communication channel are chosen or selected, inparticular in order to avoid spectral ranges where other and externalradio sources and/or radio services exist, are present and/or areactive.

Still a further embodiment is proposed, wherein said PLC modem devicemeasures the radiation of the power line channel where it is connectedto, wherein one modem device sends a well known signal as a referencesignal on the power lines channels and all participating modems receiveand/or measure this signal over a wireless channel, in particular withtheir terrestrial antenna, wherein with this measurement the modemdevices determine the radiation of the power line channel depending onfrequency, and wherein the result of this measurements is exchanged toall modem devices in order to not use or to avoid the frequencies orspectral ranges with respect to the relevant radiation for PLCcommunication.

Additionally or alternatively, said at least one PLC modem device and/orsaid possible communication partner devices communicate and/or transmitthe respective measurement data, its respective analysis results, saidcommunication quality data, said communication spectrum data, saidcommunication channel data, said communication spectrum and/or saidcommunication channel to said possible communication partner devicesand/or said at least one PLC modem device.

Further it is proposed that said processes of generating, oftransmitting said pre-defined reference signal, of measuring, ofanalyzing the measurement, and/or of communicating the respective datato said possible communication partner devices and/or said at least onePLC modem device are performed during said step of generating and/orproviding communication quality data, within said step of determining atleast communication spectrum data and/or communication channel data,and/or within said step of determining and/or selecting a communicationspectrum and/or a communication channel.

It is a further aspect of the present invention to provide a PLC modemdevice which is capable of and/or comprises means for realizing themethod for operating a PLC modem device according to the presentinvention.

A PLC communication or modem device according to the present inventionmay comprise means for monitoring a presence of interferences caused byoperating other PLC modem devices, caused by a communication line usedfor own power line communication and/or from operating radio servicesand may comprise means for performing power line communication in thecase that interferences from said operating other PLC modem devices,form said communication line used for own power line communicationand/or from said operating radio services are detected at most oressentially on communication channels or communication spectra wheresaid interferences from other PLC modem devices or from radio servicesare not detected, and is thereby adapted for simultaneously avoidinginterferences to and from other PLC modem devices and radio services.

According to the present invention said PLC modem device comprises meansfor performing a step of at least one of generating and providingcommunication quality data with respect to at least one communicationchannel between said PLC modem device and at least one communicationpartner device, said communication quality data being descriptive for atleast one of communication capabilities, communication quality andcommunication features of at least one of said at least onecommunication partner device and said at least one communicationchannel, means for performing a step of determining at least one ofcommunication spectrum data and communication channel data based on saidcommunication quality data and being descriptive for at least one of atleast one communication spectrum for said PLC modem device and for saidat least one communication channel each of which with respect to said atleast one communication partner device, means for performing a step ofat least one of determining and selecting at least one of acommunication spectrum and a communication channel from said at leastone communication channel each of which based on at least one of saidcommunication spectrum data and on said communication channel data, andmeans for performing a step of communicating with said at least onecommunication partner device via at least one of said selectedcommunication channel and said selected communication spectrum.

Said PLC modem device is according to the present invention adapted inorder to monitor by a measurement process at least one of possiblecommunication channels and communication spectra within said means forperforming said step of at least one of generating and providing saidcommunication quality data.

Said means for performing said step of at least one of determining andselecting at least one of a communication spectrum and a communicationchannel is adapted to at least one of select and choose at least one ofan actual communication spectrum and an actual communication channel forsaid step of communicating for which a comparable low interference fromsignal sources or signals other than the communication partner devicesassociated in said step communicating and the signal stemming therefrom, respectively, is given.

Thereby PLC modem device is adapted in order to avoid and de-allocatepartly or completely at least one of communication spectra andcommunication channels of devices and services other than devices andservices associated in said step of communication.

Thereby PLC modem device is adapted in order to avoid and de-allocatepartly or completely at least one of communication spectra andcommunication channels associated with one or a plurality of amateur, AMor DRM radio services.

Preferably, said inventive PLC modem device may comprise means for atleast one of wirelessly and by wire receiving at least one of radiosources and radio services.

Further, said inventive PLC modem device may comprise at least one of aterrestrial tuner device and an antenna device for receiving at leastone of radio sources and radio services.

A PLC communication or modem device according to the present inventionmay comprise an antenna device and an antenna interface (AI) connectedthereto for receiving radio sources and/or radio services and forfeeding and providing respective signals for evaluation.

A PLC communication or modem device according to the present inventionmay comprise a power line sensing means and/or a terrestrial tunerdevice as well as a power line interface connected thereto for receivingradio sources and/or radio services and for feeding and providingrespective signals for evaluation.

A PLC communication or modem device according to the present inventionmay comprise an evaluating and estimation unit for evaluating radiationsand/or noise and for estimating channel.

A PLC communication or modem device according to the present inventionmay comprise a central processing unit or CPU which is connected to saidantenna Interface and/or to said power line interface, in particular forcontrolling the same.

Additionally, it is a further aspect of the present invention to providea communication arrangement or a communication network, which is capableof and/or comprises means for realizing the method for operating acommunication arrangement according to the present invention and/or thesteps thereof and/or which comprises a plurality of PLC modem devicesaccording to the present invention.

Furthermore, a computer program product is provided according to thepresent invention which comprises computer program means which iscapable of performing and/or realizing the method for operating a PLCmodem device according to the present invention and/or the method foroperating a communication arrangement according to the present inventionand/or the steps thereof, when it is executed on a computer, a digitalsignal processing means and/or the like.

Finally, a computer readable storage medium is provided by the presentinvention which comprises a computer program product according to thepresent invention.

In the following, these and further aspects of the second concept of thepresent invention will be elucidated in more detail taking account tothe following remarks:

The present invention relates in particular to the spectrum placement ofPLC communication.

Depending on e.g. measured SNR and distance between communicating PLCmodems their Communication Spectrum shall be placed in the frequencydomain.

Known PLC Modems today allocate a predefined communication spectrum infrequency domain. Therefore, known PLC Modems today do not use theavailable bandwidth efficiently. According to the present invention thisis optimized by intelligent placement of the Communication spectrum.

-   -   Using better spectrum placements coexistence problems between        PLC modems can be solved.    -   Available Bandwidth can be used more efficiently which results        in higher throughput capabilities.

Every node participating in PLC communications measures Noise on thepower line, attenuation and distance to the communication partner.

With the knowledge of the transmission level, attenuation and noise theavailable SNR can be calculated. Channel capabilities can be calculatedfor various possible communication windows of the SNR graph. The newinitiated communication shall be placed to a frequency location wherethe calculated Channel Capability fits best to the demanded transmissioncapability.

If a later starting communication decides to use the same frequencylocation that was already allocated by an other communication thecommunication of the shorter distance between the modems shall move to asecond “best fit” location at a higher frequency. The communication viathe longer distance shall use the spectrum at lower frequencies.

The background behind this mechanism is:

Statistically PLC Channel via longer distances between the modems havehigher attenuation than short distance communication. To use frequencyspectrum efficient short distance communication shall use higherfrequencies, long distance communication shall use lower frequencies(see FIG. 5).

This Invention and its technology may be useful for and applied to DSLand xDSL communication, as well.

Every node participating in PLC communications measures noise on thepower line, attenuation and distance to the communication partner.

Here, a short description on how to measure these parameters is given:

-   -   The transmitted signal is known to all modems.    -   Transmitting a known signal and measuring this at the receiver        side attenuation between two modems can be calculated.    -   Snooping on the power line wire locally at the receiver measures        the noise.    -   With the knowledge of the transmission level, attenuation and        noise the available SNR can be calculated.

Channel capabilities can be calculated for various possiblecommunication windows of the SNR graph. E.g. possible communicationwindows can be found in FIG. 4 from 20 MHz to 40 MHz, 50 MHz to 60 MHzor 60 MHz to 80 MHz.

The new initiated communication shall be placed to a frequency locationwhere the calculated channel capability fits best to the demandedtransmission capability.

PLC Modems may embed a terrestrial tuner and antenna. Said modems maysnoop in the air if there are any radio services and/or radio sourcesavailable. If a relevant service and/or source is found at any frequencylocation the respective frequency band is or shall be omitted in powerline communication. Because due to radiation of the power lines theremay be a loss of quality at these services if the identical frequenciesare used for PLC as well.

Next the PLC modem shall measure the radiation of the power line channelwhere it is connected to. One modem sends a well known signal as areference signal on the power lines channel and all participating modemsreceive and/or measure this signal over a wireless channel, inparticular with their terrestrial antenna. With this measurement themodems determine the radiation of the power line depending on frequency.The result of this measurements shall be exchanged to all modems, so thefrequencies with relevant radiation shall not be used for PLC, as well.

There are various possibilities to measure the distance between twocommunication partners:

-   -   Measuring transfer function in frequency domain, calculation of        channel impulse response, selecting the main impulse, calculate        distance with the help of signal transmission speed and the time        of arrival of main impulse    -   Measuring Impulse Response in time domain with the help of        pn-sequences and calculate distance with the help of the arrival        time of the main impulse and of the of signal transmission        speed.

If a later starting communication decides to use the same frequencylocation that was already allocated by an other communication thecommunication of the shorter distance between the modems shall move to asecond “best fit” location at a higher frequency. The communication viathe longer distance shall use the spectrum at lower frequencies.

The PLT system shall implement a so called ‘Distance Map’ that storesthe distances between all PLT modems to each other. The ‘Distance Map’must be readable from all modems. Arbitration of the frequencyallocation shall be done with the help of the distance map.

These and further aspects of the present invention will be furtherdiscussed in the following based of preferred embodiments of theinvention by taking reference to the accompanying and schematicalfigures.

FIG. 1 is a schematical block diagram elucidating a communicationenvironment which can be managed by the inventive method for power linecommunication.

FIG. 2 is a schematical block diagram elucidating a typical MACstructure.

FIG. 3 is a diagram elucidating a possible signal-to-noise-ratio SNR ina power line communication channel and the selection of theconstellation for each carrier.

FIG. 4 is a schematical block diagram elucidating the time structureaccording to which the communication within a system of FIG. 1 can beestablished for TD coexistence approach aspects.

FIGS. 5-8 are schematical graphical representations for elucidatingaspects of communication conditions in a process of power linecommunication for FD coexistence approach aspects.

FIG. 9 is a schematical block diagram elucidating an embodiment of areceiving power line communication partner device.

FIG. 10 is a schematical block diagram elucidating an embodiment of asending or transmitting power line communication partner device.

FIGS. 11, 11A, 11B is a schematical block diagram elucidating apreferred embodiment of the inventive method for operating a PLC modemdevice.

FIG. 12 is a schematical block diagram elucidating the basic aspects ofthe inventive method for operating a PLC modem device and of aninventive communication arrangement.

FIGS. 13-15 described by means of graphical representations of differentspectra, several aspects of the present invention.

FIGS. 16A, 16B schematically describe relevant radiation situations.

FIG. 17 demonstrates some device aspects of a PLC modem device accordingto the present invention are described by means of a schematical blockdiagram.

In the following structural and/or functional elements which arecomparable, similar or equivalent with respect to each other will bedenoted by identical reference symbols. Not in each case of theiroccurrence a detailed description will be repeated.

FIG. 1 is a schematical block diagram elucidating a possible structurefor a communication environment 100 to which an embodiment of theinventive power line communication method can be applied. Said acommunication environment 100 can be referred to as a global network ofdevices which may by one means or another interact with each other.

The a communication environment 100 shown in FIG. 1 comprises a firstpower line communication system P which is situated in a first apartmentof flat 1 and a second power line communication system P′ which issituated in a second apartment of flat 2 which is spatially separatedfrom said first apartment of flat 1.

The first power line communication system P comprises in the exampleshown in FIG. 1 three power line communication partner devices P1, P7,and P10. Between power line communication partner device P1 and powerline communication partner device P10 a power line communication shallbe established or is in progress which is indicated by the arrowpointing from the first or sending power line communication partnerdevice P1 to the second or receiving power line communication partnerdevice P10.

As on the other hand within the second power line communication systemP′ a communication between a sending power line communication partnerdevice P15 and a receiving power line communication partner device P21is in progress or shall be maintained which is indicated by the arrowpointing from power line communication partner device P15 to power linecommunication partner device P21 and interference or crossed for processor effect which is indicated by the doted arrow may take place by thesending power line communication partner device P15 of the second powerline communication system P′ to the receiving power line communicationpartner device P10 of the first power line communication system P.

The inventive method for power line communication is established inorder to avoid the draw backs of cross-talk and interference in powerline communication systems as shown in FIG. 1.

FIG. 2 is a schematical block diagram of a MAC frame structure accordingto which power line communication between a first or sending power linecommunication partner device P1 and a second or receiving power linecommunication partner device P10 as shown in FIG. 1 can be realized.According to FIG. 2 the data to be communicated between interactingpower line communication partner devices P1, P10 are transmitted withinthe structure of so-called MAC frames or media access control frames asshown in FIG. 2. The data is distributed within a concatenation of MACframes, each of which are composed of five major sections, namely thebroadcast channel section, a downlink face section, a direct link facesection, an uplink face section, as well as a resource face section.

FIG. 4 is a schematical block diagram elucidating communication betweenpower line communication partner devices P1, P10 on the one hand andP15, P21 on the other hand. The blocks with solid lines indicate datacommunication between the first or sending power line communicationpartner device P1 and the second or receiving power line communicationpartner device P10 of the first power line communication system P,whereas the dashed block indicates the data communication between thesending power line communication partner device P15 and the receivingpower line communication partner device P21 of the second power linecommunication system P′. Each of the blocks correspond to respectivetime slots which are assigned to the respective pairs of power linecommunication partner devices P1, P10 and P15, P21 of said first andsaid second power line communication systems P, P′ respectively, inorder to avoid interference and cross-talk problems between said firstand second system P, P′.

FIGS. 5 to 8 elucidate by means of graphical representations thetransmission and receiving situations in said first and second powerline communication systems P, P′ shown in FIG. 1.

FIG. 5 elucidates the attenuation of a signal which is transmitted fromsaid first or sending power line communication partner device P1 of saidfirst power line communication system P to said second or receivingpower line communication partner device P10 of said first power linecommunication system P. The trace of FIG. 5 describes the attenuation indB as a function of frequency of the transmitted signal. Here theattenuation is measured at the location of the second power linecommunication partner device P10 of said first power line communicationsystem P.

FIG. 6 includes as a additional trace the attenuation of a signaltransmitted from the sending power line communication partner device P15of the second power line communication system P′ at the location of thesecond or receiving power line communication partner device P10 of thefirst power line communication system P. Obviously, there existfrequency bands in which the signal emitted from the sending power linecommunication partner device P15 of the second power line communicationsystem P′ is less attenuated at the location of the second or receivingpower line communication partner device P10 of the first power linecommunication system P when compared to the attenuation of the signalemitted from the first or sending power line communication partnerdevice P1 of said first power line communication system P. Therefore,there exists sections in the frequency spectrum where the interferenceor cross-talk signal has a superior signal strength over the data signalto be received by said second or receiving power line communicationpartner device P10 of the first power line communication system P.

In FIG. 7 the frequency bands are emphasized and indicated at which thelatter described situation is not given, i.e. the scattered sections arefrequency sections at which the signal strength for the data signaltransmitted from first or sending power line communication partnerdevice P1 is larger than the signal interfered from the sending powerline communication partner device P15 of the second power linecommunication system P′ at the location of the second or receiving powerline communication partner device P10 of said first power linecommunication system P.

FIG. 8 elucidates a situation in which the emphasized sections shown inFIG. 7 are freed from emissions of the sending power line communicationpartner device P15 of the second power line communication system P′ inorder to increase the signal-to-noise ratio at the respective frequencybands for the data signal transmission from said first or sending powerline communication partner device P1 to said second or receiving powerline communication partner device P10 of said first power linecommunication system P thereby increasing the possible communicationband width and data throughput.

These and further aspect will also be become more clear based on thefollowing description:

In the following elements and structures which are equivalent orcomparable with respect to their function and/or the structure will beindicated by the same reference symbols and their explicit descriptionwill not be repeated in each case of their occurrence.

FIG. 11 is a schematical block diagram containing a flow chart for apreferred embodiment of the inventive method for operating a PLC modemdevice according to the present invention.

Dearing a first section a step S1 a of detecting communication partnerdevices CP and additionally or alternative a step S1 b of detectingcommunication channels CC are performed. These both steps S1 a and S1 bmay be alternatives, however, they may be also performed both. Therebyinformation with respect to possible communication partner devices CPand/or possible communication channels CC with respect to saidcommunication partner devices CP can be obtained.

In a following step S2 of a following section of the inventive methodfor operating a PLC modem device communication quality data CQD aredetermined, detected and/or derived on the basis of the informationobtained from steps S1 a and S1 b. This step S2 of detectingcommunication quality data CQD may comprise detecting processes ormeasuring processes with respect to signal attenuation, signaltransmission level, noise, and/or signal-to-noise-ratio.

In a following section of the inventive method for operating a PLC modemdevice a step S3 a of determining communication spectrum data CSD and/ora step S3 b of determining communication channel data CCD are performed.Both steps S3 a and S3 b may be performed alternatively or both so as toderive information which is descriptive for the spectra which might beused for future communication processes and/or information with respectto possible applicable communication channels.

Based on the determined communication spectrum data CSD and thecommunication channel data CCD in a following section a communicationspectrum CS and/or a communication channel CC may be selected among thepossible communication spectra and/or among the possible communicationchannels, respectively, by performing respective processing steps S4 aand S4 b, respectively.

Finally, in a final step S5 the selected communication spectrum CSand/or the respective selected communication channel CC are used forestablishing a communication between said PLC modem device and aselected or given communication partner device CP.

FIGS. 11A and 11B show in more detail sub-process of general schemeshown in FIG. 11, in particular a sub-process during a networkinitialization phase and a sub-process during a network communicationphase, respectively. The respective steps T0 to T8 and U1 to U7 and U1′to U3′ of the schemes of FIGS. 11A and 1B, respectively are essentiallyself-explanatory.

FIG. 11A describes a possible network initialization phase comprising asub-process T0 of arbitration and sub-processes of measurements andevaluation T1 to T8. Finally, the respective communication quality dataCQD and the like are available.

FIG. 11B describes the possible communication management of two pairs ofPLC modems 10, PLC. Steps U1 to U3 describe the establishment of thecommunication of the first pair of PLC modems, i.e. between a first anda second PLC modem. Steps U1′ and U2′ described a communicationpre-phase for the second pair of PLC modems, i.e. between a third and afourth PLC modem. Steps U4 to U6 and U3′ describe the negotiationbetween the two pairs to establish an appropriate communicationstructure which fits best or better.

FIG. 12 demonstrates by means of a schematical block diagram acommunication arrangement 1 or communication network 1 to which theinventive method for operating a PLC modem device or for operating acommunication arrangement/network may be applied to.

The communication network 1 or communication arrangement 1 of FIG. 12comprises a power line carrier modem device or PLC modem device 10, PLC,Additionally said arrangement or network 1 further comprises possiblecommunication partner devices 20, 21, 22, CP. In the case of theembodiment of FIG. 12 the PLC modem device 10, PLC is connected to saidcommunication partner device 20, CP by communication channels 31, 32,CC. For respective connections between and to the other communicationpartner devices 21, 22 further communication channels 33-39, CC areprovided.

When applying the inventive method for operating the PLC modem device10, PLC it may first be checked which communication channels areavailable for communicating to the appropriate communication partnerdevice 20, CP. After the respective communication channels 31 and 32 arefound respective communication quality data CQD are collected andevaluated on the basis of which respective communication spectrum dataCSD as well as communication channel data CCD are derived. Based on thederived communication spectrum data CSD and communication channel dataCCD for a next communication to be established between said PLC modemdevice 10 and the respective communication partner device 20 arespective channel and a respective spectrum for the communication areselected.

The selection is realized to establish a communication which fits bestto the communication, spectrum and channel capabilities of thecommunication arrangement or communication network 1 at the actual andpresent status.

According to preferred embodiments of the inventive method for operatinga communication arrangement or a communication network 1 every node andtherefore every PLC modem device is enabled to measure the noise on therespective power line, the attenuation of the signal and the distance tothe respective communication partner devices. FIG. 13 demonstratesdifferent measurement results which might occur during the process ofoperation and during the process of communication.

FIG. 13 is a graphical representation of the signal level as a functionof the frequency of the signal. Trace CS1 demonstrates the transmittedsignal or reference signal which is known to all nodes participating inthe PLC communication process. The trace indicated by CS2 represents thereceived signal after transmission and shows a respective andtransmission dependent damping with respect to the original signal CS1.Finally, the trace indicated by CS3 demonstrates the local noiseobtained during a respective transmission process. As the transmittedsignal is known to all nodes and therefore known to all participatingPLC modem devices and the transmitted version of the known signal can bemeasured at the receiving side or receiver side, the respectiveattenuation between two participating devices, i.e. the sending PLCmodem device and a receiving communication partner device CP or viceversa can be calculated. Therefore, by snooping on the power line wirelocally the noise at the receiver side can be measured. With theknowledge of the transmission level, the attenuation of the signal andthe noise, the available signal-to-noise-ratio can be calculated.

FIG. 14 is a spectral representation of the signal-to-noise-ratio SNR.

The signal to noise ratio SNR may be calculated by using Shannons lawaccording to equation (3) above, which reads in this case:SNR:=Ptransmit_([dBμV])−Attenuation_([dB])−Noise_([dB]).

In the case of the situation shown in FIGS. 13 and 14 this leads toSNR:=CS2−CS3, with Ptransmit_([dBμV])=CS1.

The respective channel capability C is then

C := ∫_(f_(start))^(f_(stop))ld(1 − SNR(f)) 𝕕f.with f_(Start) and f_(Stop) denoting the frequency band's boundaries forthe required bandwidth Bw:Bw:=f_(Stop)−f_(Start).

In FIG. 14 one can ranges with comparable high values for SNR from 20MHz to 40 MHz, from 50 MHz to 60 MHz, as well as from 60 MHz to 80 MHz.

FIG. 15 is a spectral representation of the signal attenuation along acommunication channel so as to demonstrate the attenuation level as afunction of the distance between two communicating devices. In FIG. 15the trace indicated by CS4 shows the attenuation of the transmittedsignal for a long distance channel. The trace indicated by CS5demonstrates the attenuation level of a medium distance channel.Finally, the trace indicated by CS6 demonstrates the attenuation levelfrom a short distance communication channel.

FIGS. 16A and 16B demonstrate schematically the radiation situations thepresent invention can deal with.

In the situation shown in FIG. 16A the PLC modem device 10, PLC snoopsin the air in order to detect external radio services or radio sourcesof relevance. When establishing communication to the communicationpartner device 20, CP via a communication channel 31, CC which is apower line channel the frequencies or spectral ranges of the externalradio sources or radio services are avoided or not used in order toavoid interferences to the external radio sources or radio services viaradiation coming from the power line and the communication processbetween the modem devices 10 and 20 and/or from said external radiosources or radio services coming from said external radio sources orradio services via said power line channel 31, CC.

In the situation shown in FIG. 16B the PLC modem device 10, PLC snoopsin the air in order to detect radiation from the power line channel 31,CC itself.

In FIG. 17 some device aspects of a PLC modem device 10, PLC accordingto the present invention are described by means of a schematical blockdiagram.

Power line communication is realized by connecting said PLC modem device10, PLC via a power line interface PLI to e.g. a socket of a power linesystem. transmitted and received data are composed and analyzed,respectively, by a provided CPU and an evaluating and estimating unitEEU. In addition, an antenna A together with an antenna interface AI areprovided in order to wirelessly receive signals with respect to certaincommunication channels 31, 32, CC and/or communication spectra CS. Bymeans of the evaluating and estimating unit EEU radiation, noise,interferences, and channel quality can be estimated. In order to ensurehigh PLC quality communication spectra CS and/or communication channels31, 32, CC may be changed and/or the transmission conditions, e.g. thetransmission power, may be adapted, with or without changingcommunication spectra CS and/or communication channels 31, 32, CC.

Power control unit PC is adapted in order to adjust the power level forPLC transmission and for realizing the power back off and QoS concepts.

In the sense of the present invention the above and below listedfeatures may be arbitrarily combined.

Reference Symbols 100 communication environment Ch1, . . . , ChnPossible communication channels in 1^(st) PLC system P Ch1′, . . . ,Chn′ Possible communication channels in 2^(nd) PLC system P′ P firstpower line communication system P′ second power line communicationsystem P1 first or sending power line communication partner device P7power line communication partner device P10 second or receiving powerline communication partner device P15 sending power line communicationpartner device P21 receiving power line communication partner device 1communication arrangement, communication network according to thepresent invention 10 PLC modem device, PLC modem 20 communicationpartner device 21 communication partner device 22 communication partnerdevice 31-39 communication channel CC communication channel CCDcommunication channel data CP communication partner device CQDcommunication quality data CSD communication spectrum data CScommunication spectrum PLC PLC modem device, PLC modem A Antenna,antenna device AI Antenna interface CPU Central Processing Unit,Processor EEU Estimation and Evaluation Unit M Memory PC Power Control,Power Level Control PLI Power line Interface S Socket, PLC socket, PLCconnection means

The invention claimed is:
 1. A method for operating a PLC modem devicein a communication arrangement, comprising: performing a process ofchecking at least one of the presence, existence and activity of atleast one of external radio sources and radio services to detect ifthere are any radio services and/or radio sources available; and in thecase that at least one of external radio sources and radio servicesexist, are present and are active, performing power line communicationon communication channels or communication spectra where at least one ofthe presence, existence and activity of the at least one of externalradio sources and radio services is not detected, to avoid or reduceinterferences to and from at least one of external radio sources andradio services.
 2. The method for operating a PLC modem device in acommunication arrangement according to claim 1, comprising: at least oneof generating and providing communication quality data with respect toat least one communication channel between said PLC modem device and atleast one communication partner device, said communication quality databeing descriptive for at least one of communication capabilities,communication quality and communication features of at least one of saidat least one communication partner device and said at least onecommunication channel; determining at least one of communicationspectrum data and communication channel data based on said communicationquality data and being descriptive for at least one of at least onecommunication spectrum for said PLC modem device and for said at leastone communication channel each of which with respect to said at leastone communication partner device; performing a process of checking atleast one of the presence, existence and activity of at least one ofexternal radio sources and radio services to detect if there are anyradio services and/or radio sources available; at least one ofdetermining and selecting at least one of a communication spectrum and acommunication channel from said at least one communication channel eachof which based on at least one of said communication spectrum data andon said communication channel data, wherein spectral ranges, where atleast one of external radio sources and radio services at least one ofexist, are present and are active, are avoided; and communicating withsaid at least one communication partner device via at least one of saidselected communication channel and said selected communication spectrum,to at least one of reduce and avoid at least one of disturbances andinterferences with, to and/or from at least one of external radiosources and/or radio services.
 3. The method according to claim 1,wherein, if a relevant external radio service and/or radio source isfound at any frequency location, the respective frequency band isomitted in power line communication.
 4. The method according to claim 1,wherein within said process of checking the presence, existence and/oractivity of external radio sources and/or radio services at least one ofsaid PLC modem device and at least one communication partner devicesnoops in the air if there are any radio services and/or radio sourcesavailable.
 5. The method according to claim 4, wherein snooping in theair is performed with a separate antenna device for receiving radiosources and/or radio services.
 6. The method according to claim 4,wherein snooping in the air is performed with a terrestrial tuner devicefor receiving radio sources and/or radio services.
 7. The methodaccording to claim 1, wherein said process of checking the presence,existence and/or activity of external radio sources and/or radioservices is performed in a wireless manner and/or in a wired manner. 8.The method according to claim 1, wherein the external radio sourcesand/or radio services are associated with one or a plurality of amateur,AM or DRM radio services.
 9. The method according to claim 2, furthercomprising: monitoring at least one of possible communication channelsand communication spectra by a measurement process within said step ofat least one of generating and providing said communication qualitydata, and wherein, in said step of at least one of determining andselecting at least one of a communication spectrum and a communicationchannel, at least one of an actual communication spectrum and an actualcommunication channel is selected and chosen for said step ofcommunicating for which a comparable low interference from signalsources or signals other than the communication partner devicesassociated in said step communicating and the signal stemming therefrom, respectively, is given.
 10. The method according to claim 9,wherein said measurement process is performed wirelessly.
 11. The methodaccording to claim 10, wherein said measurement process is performed bymeans of an antenna as a part of said PLC modem device.
 12. The methodaccording to claim 9, wherein said measurement process is performed bywire.
 13. The method according to claim 9, wherein said measurementprocess is performed by a sensor means connected to a respectivecommunication wire means.
 14. The method according to claim 9, whereinsaid actual communication conditions are chosen to effect and select atleast one of the group comprising a frequency band, a signal modulationscheme, a time slot, a transmission power, a transmission gain and areception gain each of a possible or of said actual communicationchannel of the plurality of possible communication channels between saidat least one first or sending power line communication partner deviceand said at least one second or receiving, power line communicationpartner device.
 15. The method according to claim 1, further comprisinga power back off process to avoid interference with other power linecommunication services and/or radio services by reducing transmissionpower fed or to be fed.
 16. The method according to claim 15, wherein insaid power back off process transmission power fed or to be fed isreduced to a minimum value or range which is still sufficient and/orappropriate for enabling and/or maintaining loss free or essentiallyloss free power line communication.
 17. The method according to claim15, wherein said power back off process is performed individually forone or a plurality of different channels and/or carriers.
 18. The methodaccording to claim 15, wherein said power back off process is performedon a distinct channel and/or carrier if an actual signal to noise ratioof said given channel and/or carrier is better than a signal to noiseratio necessary for an actual bit loading in said given channel and/orcarrier.
 19. The method according to claim 1, wherein power linecommunication is performed with a transmission gain and/or transmissionpower on the transmission side which fits to at least one of a maximumsensitivity, maximum input gain and minimum input attenuation on areceiving side.
 20. The method according to claim 19, wherein saidtransmission gain and/or transmission power of said transmission side isat least one of set, requested, communicated and negotiated by or withsaid receiving side.
 21. The method according to claim 15, wherein saidpower back off process is performed to adjust transmission gain and/ortransmission power in accordance to at least one of attenuations anddistances to be bridged between devices under communication, or toreduce said transmission gain and/or transmission power for comparableshort distances.
 22. The method according to claim 1, whereintransmission gain and/or transmission power are raised to increase apossible quality of service value or QoS value for quality of servicedata streams or QoS streams.
 23. The method according to claim 22,wherein information and/or signal components which need a higher QoSvalue are assigned and mapped to certain carriers, and wherein saidcertain carriers are given an increased amplitude and/or transmissionpower in the power line communication process.
 24. The method accordingto claim 22, wherein said increased amplitude and/or transmission powerfor the power line communication process are achieved by operating arespective spectral interleaver device to assign and map saidinformation and bits which need a higher QoS value to said respectivecarriers.
 25. The method according to claim 22, wherein said process ofraising said transmission gain and/or transmission power is performed ina way still enabling and/or maintaining avoidance and de-allocationpartly or completely at least one of communication spectra andcommunication channels of devices and services other than devices andservices associated in said step of communication, and/or avoidance andde-allocation partly or completely at least one of communication spectraand communication channels associated with one or a plurality ofamateur, AM or DRM radio services.
 26. The method according to claim 2,wherein said step of at least one of generating and providingcommunication quality data comprises a process of determining and/ormeasuring noise of said at least one communication channel, or of apower line thereof.
 27. The method according to claim 2, wherein saidstep of generating and/or providing communication quality data comprisesa process of determining and/or measuring a signal attenuation of saidat least one communication channel, or of a power line thereof.
 28. Themethod according to claim 2, wherein said step of generating and/orproviding communication quality data comprises a process of determiningand/or measuring a signal transmission level of said at least onecommunication channel, or of a power line thereof.
 29. The methodaccording to claim 2, wherein said step of generating and/or providingcommunication quality data comprises a process of determining and/ormeasuring a distance of said PLC modem device to said communicationpartner device with respect to said at least one communication channel,or with respect to a power line thereof.
 30. The method according toclaim 2, wherein said step of generating and/or providing communicationquality data comprises a process of determining and/or measuring asignal-to-noise ratio with respect to said at least one communicationchannel, or of a power line thereof and/or based on said noise,attenuation, signal transmission level, distance determined and/ormeasured.
 31. The method according to claim 1, further comprising atleast one of: detecting at least one communication partner device, whichis connected to said PLC modem device via at least one communicationchannel; and detecting said at least one communication channel betweensaid PLC modem device and at least one communication partner device. 32.The method according to claim 1, wherein for said at least onecommunication partner device a plurality of communication channels, orof all available communication channels, are analyzed, within said stepsof detecting said at least one communication partner device and/or saidat least one communication channel, within said step of generatingand/or providing said communication quality data, within said step ofdetermining at least said communication spectrum data and/or saidcommunication channel data, and/or within said step of determiningand/or selecting said communication spectrum and/or said communicationchannel.
 33. The method according to claim 1, wherein a communicationspectrum and/or a communication channel are selected and/or used whichare not simultaneously used by communication processes of and/or betweenother communication partner devices within said communication network orcommunication arrangement, and/or within said step of determining and/orselecting a communication spectrum and/or a communication channel. 34.The method according to claim 1, wherein for a communication channelhaving or realizing a larger communication distance between said PLCmodem device and said selected communication partner device a lowerfrequency range is chosen for said communication spectrum, or withinsaid step of determining and/or selecting a communication spectrum. 35.The method according to claim 1, wherein for a communication channelhaving or realizing a shorter communication distance between said PLCmodem device and said selected communication partner device acommunication spectrum with a higher frequency range is chosen, orwithin said step of determining and/or selecting a communicationspectrum.
 36. A method for operating a communication arrangement,wherein said communication arrangement includes a plurality of PLC modemdevices, said method comprising: performing the method for operating aPLC modem device according to claim 1 for at least one of said PLC modemdevices.
 37. The method according to claim 36, wherein a pre-definedreference signal is generated by at least one PLC modem device andtransmitted via at least one available communication channel, whereinpossible communication partner devices measure said pre-definedreference signal via said at least one available communication channeland/or analyze the respective measurement data, and wherein based onsaid measurements said communication quality data, said communicationspectrum data, said communication channel data, said communicationspectrum and/or said communication channel are chosen or selected, toavoid spectral ranges where external radio sources and/or radio servicesexist, are present and/or are active.
 38. The method according to claim36, wherein a pre-defined reference signal is generated by at least onePLC modem device and transmitted via at least one availablecommunication channel, wherein possible communication partner devicesmeasure said pre-defined reference signal via channels other than saidavailable communication channels and/or analyze the respectivemeasurement data, and wherein based on said measurements saidcommunication quality data, said communication spectrum data, saidcommunication channel data, said communication spectrum and/or saidcommunication channel are chosen or selected, to avoid spectral rangeswhere external radio sources and/or radio services exist, are presentand/or are active.
 39. The method according to claim 36, wherein said atleast one PLC modem device measures the radiation of the power linechannel where it is connected to, wherein one modem device sends a wellknown signal as a reference signal on the power lines channels and allparticipating modems receive and/or measure this signal over a wirelesschannel, wherein with this measurement the modem devices determine theradiation of the power line channel depending on frequency, and whereinthe result of this measurements is exchanged to all modem devices to notuse or to avoid the frequencies or spectral ranges with respect to therelevant radiation for PLC communication.
 40. The method according toclaim 36, wherein said at least one PLC modem device and/or saidpossible communication partner devices communicate and/or transmit therespective measurement data, its respective analysis results, saidcommunication quality data, said communication spectrum data, saidcommunication channel data, said communication spectrum and/or saidcommunication channel to said possible communication partner devicesand/or said at least one PLC modem device.
 41. The method according toclaim 36, wherein said processes of generating, of transmitting saidpre-defined reference signal, of measuring, of analyzing themeasurement, and/or of communicating the respective data to saidpossible communication partner devices and/or said at least one PLCmodem device are performed during said step of generating and/orproviding communication quality data, within said step of determining atleast communication spectrum data and/or communication channel data,and/or within said step of determining and/or selecting a communicationspectrum and/or a communication channel.
 42. A PLC modem device,comprising: means for realizing the method for operating a PLC modemdevice according to the method of claim
 1. 43. The PLC modem deviceaccording to claim 42, further comprising: means for performing aprocess of checking at least one of the presence, existence and activityof at least one of external radio sources and radio services to detectif there are any radio services and/or radio sources available; andmeans for performing power line communication, in the case that at leastone of external radio sources and radio services at least one of exist,are present and are active, at most or essentially on communicationchannels or communication spectra where at least one of the presence,existence and activity of at least one of external radio sources andradio services is not detected, to simultaneously avoid or reduceinterferences to and from at least one of external radio sources andradio services.
 44. The PLC modem device according to claim 42,comprising: means for at least one of generating and providingcommunication quality data with respect to at least one communicationchannel between said PLC modem device and at least one communicationpartner device, said communication quality data being descriptive for atleast one of communication capabilities, communication quality andcommunication features of at least one of said at least onecommunication partner device and said at least one communicationchannel; means for determining at least one of communication spectrumdata and communication channel data based on said communication qualitydata being descriptive for at least one of at least one communicationspectrum for said PLC modem device and for said at least onecommunication channel each of which with respect to said at least onecommunication partner device; means for performing a process of checkingat least one of the presence, existence and activity of at least one ofexternal radio sources and radio services to detect if there are anyradio services and/or radio sources available, means for at least one ofdetermining and selecting at least one of a communication spectrum and acommunication channel from said at least one communication channel eachof which based on at least one of said communication spectrum data andon said communication channel data, wherein spectral ranges, where atleast one of external radio sources and radio services at least one ofexist, are present and are active, are avoided; and means forcommunicating with said at least one communication partner device via atleast one of said selected communication channel and said selectedcommunication spectrum.
 45. The PLC modem device according to claim 44,wherein said PLC modem device is adapted to monitor by a measurementprocess at least one of possible communication channels andcommunication spectra within said means for at least one of generatingand providing said communication quality data, and wherein said meansfor at least one of determining and selecting at least one of acommunication spectrum and a communication channel is adapted to atleast one of select and choose at least one of an actual communicationspectrum and an actual communication channel for communicating, forwhich a comparable low interference from signal sources or signals otherthan the communication partner devices associated in communicating andthe signal stemming there from, respectively, is given, to avoid andde-allocate partly or completely at least one of communication spectraand communication channels of devices and services other than devicesand services associated in said step of communication.
 46. The PLC modemdevice according to claim 42, wherein the means for performing a processof checking at least one of the presence, existence and activity of atleast one of external radio sources and radio services to detect ifthere are any radio services and/or radio sources available is capableof receiving at least one of radio sources and radio services at leastone of wirelessly and by wire.
 47. The PLC modem device according to 42,wherein the means for performing a process of checking at least one ofthe presence, existence and activity of at least one of external radiosources and radio services to detect if there are any radio servicesand/or radio sources available comprises a terrestrial tuner device forreceiving radio sources and/or radio services.
 48. The PLC modem deviceaccording to 42, wherein the means for performing a process of checkingat least one of the presence, existence and activity of at least one ofexternal radio sources and radio services to detect if there are anyradio services and/or radio sources available comprises a separateantenna for receiving radio sources and/or radio services.
 49. The PLCmodem device according to claim 42, wherein the means for performing aprocess of checking at least one of the presence, existence and activityof at least one of external radio sources and radio services to detectif there are any radio services and/or radio sources available comprisesan antenna device and an antenna interface connected thereto forreceiving radio sources and/or radio services and for feeding andproviding respective signals for evaluation.
 50. The PLC modem deviceaccording to claim 42, comprising a power line sensing means and/or aterrestrial tuner device as well as a power line interface connectedthereto for receiving radio sources and/or radio services and forfeeding and providing respective signals for evaluation.
 51. The PLCmodem device according to claim 42, comprising an evaluating andestimation unit for evaluating radiations and/or noise and forestimating channel.
 52. The PLC modem device according to claim 42,comprising a central processing unit which is connected to said antennainterface and/or to said power line interface, and configured to controlthe same.
 53. A communication system, comprising means for performingthe method according to claim
 36. 54. A communication system comprisinga plurality of PLC modem devices according to claim
 42. 55. Anon-transitory computer-readable medium encoded with computer-readableinstructions thereon, the computer-readable instructions when executedby a processor cause the processor to perform a method according to themethod of claim
 1. 56. A non-transitory computer-readable medium encodedwith computer-readable instructions thereon, the computer-readableinstructions when executed by a processor cause the processor to performa method according to claim 36.